Let's imagine it's August 2012. The Olympics is in London and Usain Bolt powers home first in the 100 metres. But when he gets to the podium, he's given the bronze medal and the athlete who came second gets the gold.
Sounds ridiculous, doesn't it — giving the top prize to someone who didn't win? But that's exactly what could happen in our democracy if the country chooses the Alternative Vote (AV) system in the referendum on May 5.
Change to AV and we would not only get a system that's used for national elections in just three countries — Fiji, Papua New Guinea and Australia (and there most people want to get rid of it) — we'd also get an electoral system where the person or party that comes second could be declared the winner.
| Mr Cameron says the new system is ridiculous
So how did we get here? Cast your mind back to last May. Our economy was on the brink of bankruptcy. We were spoken of in the same breath as Greece and Ireland. And, of course, the election resulted in a hung Parliament.
That's when the Conservatives and Liberal Democrats put differences aside and came together to work in the national interest. Fast forward nine months, and we've pulled our economy out of the danger zone, started fundamental reforms in welfare and education, and begun the long process of repairing our broken society.
So in its short existence, the coalition has been radical and full of purpose.
But it wouldn't have existed at all if there had not been compromise from both sides. During those coalition discussions, I wanted more assurances on capping immigration and not giving further powers to Europe. Nick Clegg (Lib. Dem leader) wanted them on voting reform.
We could have dug our heels in with respect to each others' requests but where would that have left our country? With no strong government and looking down the barrel of economic ruin.
How can it be right that the second, third, even fourth vote of someone who supports the BNP can count as much as the first vote of someone who supports one of the mainstream parties?
So concessions were made, with both of us securing our key objectives — and that's why we've got this referendum. Nick Clegg and the Liberal Democrats want you to say 'yes' to AV. I want you to say 'no'.
On this issue, I don't agree with Nick. Pure and simple. AV is unfair, unclear and unaccountable. Let me take each in turn.
First, it's not fair. The real beauty of First Past the Post is the principle of one person, one vote. Under AV, some votes count more than others.
Why? Because if you vote for a mainstream candidate who is top of the ballot in the first round, your other preferences will never be counted. But if you vote for a fringe party who gets knocked out, your other preferences will be counted. How can it be right that the second, third, even fourth vote of someone who supports the BNP can count as much as the first vote of someone who supports one of the mainstream parties?
What's more, AV isn't as proportional as people make out. Indeed, if it had been used in 1997, 2001 and 2005, Tony Blair would have got even bigger majorities. Would that really have reflected the will of the country? No.
And there's another big unfairness inherent in AV — that candidates who no one really wanted can end up winning.
Campaigners for a 'yes' vote say that under AV, an MP has to get the backing of 50 percent of the voters. But this isn't true. They don't mean 50 per cent of the votes cast, but 50 per cent of the votes counted.
That's because if you decide to mark one preference on your ballot paper — as many end up doing under AV — and your candidate is eliminated early, then that vote is discarded. The only votes that count towards the 50 per cent are the votes that make it to the final round. What a fix.
It's not so much that the winner has half the electorate behind them, more that because of a weird counting system, they have crawled over the finishing line. As Winston Churchill put it, AV allows democracy 'to be determined by the most worthless votes given for the most worthless candidates'.
If this all sounds confusing, it's because it is. And that's my second big problem with AV — it's incredibly unclear.
I could explain in one sentence how First Past the Post works: We all vote for our favourite and the candidate who gets the most votes wins. Ask someone how AV works and they'll take more like one hour.
There are so many different vagaries and outcomes that it's only a handful of Westminster elites who really get it. I just don't think we should have a voting system that people don't understand.
And this confusion would bring with it other problems, not least that it's expensive to administer as government will have to spend your money on explaining to you how it all works. This might be worth it if it gave us a political system that properly answered to the people. But that's the third big problem with AV — it doesn't. It would actually make politics less accountable.
Say what you like about First Past the Post, but it can be ruthlessly decisive in the election results it delivers. Think of 1979 — or even 1997. When the government of the day had had its day, the removal vans came rumbling down Downing Street, getting rid of the old to make way for the new.
That was the people speaking. That's real accountability. The problem with AV is that it makes decisive outcomes less likely — and the possibility of people clinging on to power more likely. If we'd used AV at the last election, there would be the chance, right now, that Gordon Brown would still be Prime Minister.
I think any system that keeps dead governments living on life support is a massive backward step for trust in our politics.
Unfair, unclear, unaccountable — for all these reasons I'm anti-AV. And for all these reasons I urge you to get out on May 5, vote in the referendum and say no to AV.
(c) Daily Mail, London